This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. As a participating member of the New York Consortium On Membrane Protein Structures (NYCOMPS), our laboratory aims at determining the crystallographic structures of some prokaryotic membrane proteins. Among them, we recently focused our efforts on key enzymes of bacterial protein export system, transport systems relevant to prokaryotic patogenicity, proteins with eukaryotic homologues expressed in the central neural system and key enzymes of lipid metabolism in both eukarya and bacteria. The overall objective of this studies is to elucidate structure-function relationship for these proteins, in order to sharpen our understanding of fundamental biological processes, or to describe potential future targets for drug design. Besides developing all the relevant methods necessary for success in protein production, purification and crystallization, we have established wide collaborations in the New York area, particularly with groups active in the fields of membrane embedded proteases, membrane transport, neurobiology and lipid metabolism. This will allow us to extend our study to a detailed functional understanding of these systems, and well beyond a simple collection of three-dimensional structures issued from a structural genomics approach. Crystallographic analysis of these projects is mostly taking place at the on the NE-CAT beam lines 24-ID-C and 24-ID-E (APS synchrotron facility at Argonne National Laboratory).